Urinary catheter assemblies for draining the bladder are increasingly used for intermittent catheterisation. Typically, urinary catheters are used by patients suffering from urinary incontinence or by disabled individuals like paraplegics or tetraplegics, who may have no control permitting voluntary urination and for whom catheterisation may be the way of urinating.
Intermittent catheters are typically inserted by the user him- or herself and sits only in the urethra and bladder for as long as it takes to empty the bladder—e.g. for about 5-10 minutes. Intermittent catheters are used every 4-6 hours to empty the bladder corresponding roughly to the interval at which people having no urinary problems would usually go to the bathroom. An important feature for the intermittent catheter is to ease the insertion into the urethra. This is done by providing the intermittent catheter with a low frictious surface. Non-limiting examples of such are hydrophilic coated catheters which are subsequently wetted by a swelling media in order to produce a low friction surface, or oil or water based gel which is applied to the catheter before insertion into the urethra.
Intermittent urinary catheters may be provided with a hydrophilic coating that needs to be wetted prior to use and thereby absorbs a considerable amount of liquid. Such a hydrophilic coating will provide a very lubricious surface that has very low-friction when the catheter is to be inserted.
Users of intermittent catheters may experience that emptying of the bladder takes long time—e.g. more than 10-15 minutes. This may at least partly be due to the fact that the user is unable to provide any pressure to the bladder, e.g. if the user is somehow spinal cord injured. This means that the urine has to exit the bladder through the catheter only through gravity forces. Furthermore, the limitation in the diameter of the catheter may also influence the flow-rate. The volumetric flow rate for a female that is not a catheter user is in average 25 ml/s—however flow rates down to 15 ml/s are within the normal margin.